memcpy.s

一个操作系统,用C语言实现开发的,我在一个浙江大学的操作系统实验网站找到.大家学习以下

# Kernel Library
# memcpy

.include "f_asm.inc"

.text

.global _memcpy

_memcpy:
	ENTER
		movl %esi, %edx
		movl %edi, %eax
		
		movl LEN(%ebp), %ecx
		movl SRC(%ebp), %esi
		movl DES(%ebp), %edi
		
		cmpl %esi, %edi
		jz done
		
		cld
		
		shrl $1, %ecx
		jnc 1f
		movsb
1:
		shrl $1, %ecx
		jnc 2f
		movsw
2:
		rep
		movsl			
		
done:		
		movl %eax, %edi
		movl %edx, %esi
		
		movl DES(%ebp), %eax
		
	LEAVE	
		ret